Method for measuring a flowing property in a resin transfer molding system

A measurement method for a molding system, the molding system comprising an upper mold and a lower mold forming a mold cavity, the method comprising:

• applying a pressure difference to a molding resin for driving the molding resin to flow into a preform in the mold cavity;
• detecting a flow front of the molding resin at a first position and a second position in the mold cavity by a detection device disposed over the upper mold;
• detecting an internal pressure of the mold cavity by a pressure sensor disposed outside the mold cavity;
• and
• calculating a local ratio of permeability to porosity of the preform based on the first position, the second position, a travelling time of the flow front from the first position to the second position, and the pressure difference,
• wherein the mold cavity does not contain an internal pressure sensor configured to detect an internal pressure of the mold cavity.